The goal of this research is to understand the structure and function of ganglion cells-the output neurons-in macaque retina. Certain cells in the retina-the photoreceptors-are stimulated by long-, medium-, or short-wavelength light. The photoreceptors pass information to bipolar cells, which in turn relay to ganglion cells, which then output to visual centers of the brain. There are also cells within the retina-horizontal and amacrine-that "hook up" to these circuits and share information with other cells within the retina. Some monkey species, like humans, share color vision based on three primaries-red, green and blue-which feed into two color-opponent channels in the brain. Our experiments are directed at determining which combinations of cell types are responsible for coding information about blue/yellow and red/green channels. We use intracellular recording and imaging in a unique preparation of living retina, combined with a three-color light, to test sensiti vity and c onnectivity of individual cells. FUNDING NIH grants RR00166, EY09625, EY06678, and EY03221. Peterson, B. and Dacey, D.M. Morphology of wide-field, monostratified ganglion cells of the human retina. Invest. Ophthal. Vis. Sci., Suppl. 39 S563, 1998 (abstract). Verweji, J., Dacey, D.M., and Buck, S.L.Receptive field size, sensitivity and dynamics of rod signals in macaque HI horizontal cells. Invest. Ophthal. Vis. Sci., Suppl. 39 S209, 1998 (abstract). Smith, V.C., Dacey, D.M., Lee, B.B., and Pokorny, J. Time dependent adaptation in primate horizontal cells. Invest. Ophthal. Vis. Sci., Suppl. 39 S209, 1998 (abstract). Lee, B.B., Dacey, D.M., Smith, V.C., and Pokorny, J. Spatial independence of adaptation in primate outer retina. Invest. Ophthal. Vis. Sci., Suppl. 39:S210, 1998 (abstract). [This project was also reported in the Neuroscience Core section.]